Brand:
LG
Category: TV
Document Type: Manual
Language: EN
Available Languages: EN , ES
Manual for L4200A
Uploaded: Nov. 21, 2025, 6:28 p.m.
Warranty Information
None
Installation and Connection:
Includes safety precautions, how to set up the monitor, connect to PC, VCR/DVD, or HDTV, and AV outputs.
Input Selection and Adjustment:Covers selecting input signals, adjusting screen settings via OSD menu for PC and video sources, and setting up PIP/POP/PBP modes.
Miscellaneous:Provides troubleshooting tips, specifications, and details on controlling multiple monitors.
Troubleshooting and error codes
| Issue | Possible Cause | Solution |
| No image is displayed | Monitor power cord not connected | See if the power cord is properly connected to the outlet. |
| Power switch is off | See if the power switch is turned on. | |
| Screen appears extremely dark | Adjust brightness and contrast. If in power saving mode, move the mouse or press any key. | |
| Power LED looks yellow | None specified in the provided text. | |
| 'OUT OF RANGE' message | PC signal out of monitor's frequency range | Adjust frequency range. Maximum resolutions: D-Sub: 1600x1200 @60Hz, DVI-D: 1360x768 @60Hz. |
| 'CHECK SIGNAL CABLE' message | Signal cable not connected | Check the signal cable. Press the 'SOURCE' button to check input signal. |
| 'Unknown Monitor' message | Driver not installed | Install monitor driver or download from www.lge.com. Check plug&play support. |
| 'CONTROLS LOCKED' message | Control locking function active | Press the Menu button and button for 5 seconds to unlock. |
| Screen image abnormal | Incorrect screen position | Press 'AUTO' button for D-Sub signal, or use Position OSD menu. Check video card resolution/frequency. |
| Thin lines on background | None specified in the provided text. | None specified in the provided text. |
| Horizontal noise/blurred characters | None specified in the provided text. | Press 'AUTO' button for D-Sub signal, or use Clock/Phase OSD menu. |
| Unable to adjust H/V position in Zoom menu | Zoom value is 0 | If Zoom is set to 0, H/V position cannot be adjusted. |
| Screen size auto-adjusted when connected to PC | None specified in the provided text. | Execute PIP/POP/PBP to change to full screen mode. |
| Brightness differs between main/sub screen | None specified in the provided text. | Brightness/tint cannot be adjusted in PIP/POP/PBP sub-screen menu. |
| After-image appears when monitor is turned off | Fixed image used for long time | Use the screensaver function. |
| Audio function does not work | Audio cable not connected | See if audio cable is connected properly. |
| Sound set improperly | See if the sound is set properly. | |
| No sound with PIP/POP/PBP mode | Sound set to Off | See if Sound is set to On in the PIP/POP/PBP menu. |
| Sound too dull | None specified in the provided text. | Select appropriate treble/bass sound. |
| Sound too low | None specified in the provided text. | Adjust the volume. |
| Screen size function in OSD menu not work | PIP/POP/PBP function in use | Screen size function may not work if PIP/POP/PBP is in use. |
| Screen color abnormal | Color settings incorrect | Set color to more than 24 bits (true color) in Control Panel - Display - Settings - Color Table. |
| Signal cable connection issue | Check signal cable connection, or re-insert PC video card. | |
| Black spots on screen | LCD panel characteristics | Pixel variations are normal for LCD panels and not a malfunction. |